1) Authority 2) Despot, often 
The mandatōr (μανδάτωρ), deriving from the Latin word for `messenger`, was a subaltern official in the middle Byzantine Empire. ==History and functions== The mandatores were a corps of messengers for special duties attached to the bureaux of all senior civil and military officials, such as the thematic stratēgoi, the commanders of the .....
• (n.) A director; one who gives a mandate or order. • (n.) The person who employs another to perform a mandate.
Man·da'tor noun [ Latin ] 1. A director; one who gives a mandate or order. Ayliffe. 2. (Rom. Law) The person who employs another to perform a mandate. Bouvier. 
[n] - an authority who issues a mandate
Specialised version of the Militant, AEC, [UK]
noun an authority who issues a mandate